1. Technical Field
The present invention relates to a board, more specifically to a noise reduction board that can reduce an electromagnetic interference (EMI) noise by using an electromagnetic bandgap structure.
2. Description of the Related Art
As the operating frequencies of electronic products become higher, electromagnetic interference (EMI) has been perceived as a chronic noise problem. Particularly, the operating frequencies of electronic products have reached a few ten MHz, or even a few GHz, making the EMI problems more serious. Subsequently, finding a solution to the problems is desperately needed. Among the EMI problems occurring at a board, a solution for the noise problems particularly occurred at the edge of the board has not been sufficiently researched, making it difficult to completely block the noise at the board.
EMI noise refers to a noise that creates a noise problem caused by interference when an electromagnetic (EM) wave generated in one electronic circuit, component or part is transferred to another electronic circuit, component or part. The EMI noise can be broadly categorized into two types, namely radiation noise (reference numerals 10 and 30 in FIG. 1) and conduction noise (reference numeral 20 in FIG. 1).
The radiation noise 10, which is radiated towards an upper side of the board (that is, the mounting surface of an electronic part), may be commonly shielded by covering an upper portion of the board by use of an electromagnetic shielding cap, for example, a metal cap. However, few studies have tried to find an effective solution for the radiation noise 30 (hereinafter, referred to as an “edge noise”), which is radiated towards the outside of the board when a conduction noise 20 inside the board is conducted to the edge of the board.
If a technology were developed to reduce the edge noise at the edge of the board through a simple modification of the board structure, it would significantly reduce the development time and costs, compared to the conventional method, which solves the problem through the use of a metal cap or a circuit. Additionally, such technology can have more merits in terms of space utilization and power consumption, and can easily remove a noise in a frequency band of a few GHz, making it effective in solving the EMI noise problem at the edge of the board.